Field of the Invention
The present invention relates to a side airbag apparatus configured to buffer shock applied from a vehicle lateral side, and particularly relates to a side airbag apparatus disposed between a vehicle body and a back seat.
Description of the Related Art
Typically, a side airbag system including an inflator configured to inject gas into an airbag, a box-shaped housing box configured to house the airbag and the inflator, and a resin base cover configured to cover the housing box from a vehicle front side has been known as a side airbag apparatus disposed between a vehicle door and a back seat in a vehicle width direction (see, e.g., JP 2009-40328).
In the side airbag apparatus described in JP 2009-40328, when the airbag housed in the metal housing box is swollen by the inflator, the airbag inflates and expands by breaking a thin portion of the resin base cover positioned on the vehicle front side.
Specifically, a shock sensor (not illustrated) detects when a shock of equal to or greater than a predetermined value is applied from a vehicle lateral side, and ignition power is supplied to the inflator. Then, the airbag inflates and expands at the side of a seated passenger.
In the side airbag apparatus described in JP 2009-40328, when the inflator operates to inflate the airbag, the gas pressure of the inflator inflating the airbag puts great load on the housing box.
For this reason, the technique has been demanded, which improves, in inflating and expansion of the airbag, the rigidity of the vicinity of the housing box housing the airbag and the inflator.
Particularly in the above-described typical technique, the housing box of the side airbag apparatus is made of metal in order to improve strength, but on the other hand, it has been demanded that the material of the housing box is changed to resin in order to reduce a weight. Even when the material of the housing box is changed to resin, the technique of improving the rigidity of the housing box in inflating and expansion of the airbag has been still demanded.